編輯：我試圖構(gòu)建一個帶有搜索功能的組合框，這就是我想出的：public class SearchableComboBox<T> extends ComboBox<T> {private ObservableList<T> filteredItems;private ObservableList<T> originalItems;private T selectedItem;private StringProperty filter = new SimpleStringProperty("");public SearchableComboBox () { this.setTooltip(new Tooltip()); this.setOnKeyPressed(this::handleOnKeyPressed); this.getTooltip().textProperty().bind(filter); this.showingProperty().addListener(new ChangeListener<Boolean>() { @Override public void changed(ObservableValue<? extends Boolean> observable, Boolean oldValue, Boolean newValue) { // If user "closes" the ComboBox dropdown list: reset filter, reset list to the full original list, hide tooltip if (newValue == false) { filter.setValue("");; setItems(originalItems); getTooltip().hide(); // If user opens the combobox dropdown list: get a copy of the items and show tooltip } else { originalItems = getItems(); Window stage = getScene().getWindow(); getTooltip().show(stage); } } });}public void handleOnKeyPressed(KeyEvent e) { //Only execute if the dropdown list of the combobox is opened if (this.showingProperty().getValue() == true) { // Get key and add it to the filter string String c = e.getText(); filter.setValue(filter.getValue() + c); //Filter out objects that dont contain the filter this.filteredItems = this.originalItems.filtered(a -> this.getConverter().toString(a).toLowerCase().contains(filter.getValue().toLowerCase())); //Set the items of the combox to the filtered list this.setItems(filteredItems); }}這個想法很簡單：只要打開組合框的下拉列表，我就會監(jiān)聽按鍵并將字符添加到過濾器中。使用這些過濾器，組合框的項目列表被過濾為僅包含包含過濾字符串的項目的列表。然后我使用 setItems 將項目列表設(shè)置為我的過濾列表。我的問題是，組合框的 valueProperty 更改，但我希望所選對象保持不變，直到用戶從下拉列表中選擇另一個。
2 回答
白板的微信
TA貢獻1883條經(jīng)驗 獲得超3個贊
我的建議是FilteredList從您的原始列表中創(chuàng)建一個。然后，使用 aPredicate過濾掉不匹配的結(jié)果。如果您將ComboBox項目設(shè)置為該過濾列表，它將始終顯示所有項目或與您的搜索詞匹配的項目。
將ValueProperty只會更新，當用戶“提交”按變化[進入]。
我在這里有一個簡短的 MCVE 應(yīng)用程序來演示整個注釋：
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.collections.transformation.FilteredList;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class Main extends Application {
// Create a list of items
private final ObservableList<String> items = FXCollections.observableArrayList();
// Create the ComboBox
private final ComboBox<String> comboBox = new ComboBox<>();
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage primaryStage) {
// Simple Interface
VBox root = new VBox(10);
root.setAlignment(Pos.CENTER);
root.setPadding(new Insets(10));
// Allow manual entry into ComboBox
comboBox.setEditable(true);
// Add sample items to our list
items.addAll("One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten");
createListener();
root.getChildren().add(comboBox);
// Show the stage
primaryStage.setScene(new Scene(root));
primaryStage.setTitle("Filtered ComboBox");
primaryStage.show();
}
private void createListener() {
// Create the listener to filter the list as user enters search terms
FilteredList<String> filteredList = new FilteredList<>(items);
// Add listener to our ComboBox textfield to filter the list
comboBox.getEditor().textProperty().addListener((observable, oldValue, newValue) ->
filteredList.setPredicate(item -> {
// If the TextField is empty, return all items in the original list
if (newValue == null || newValue.isEmpty()) {
return true;
}
// Check if the search term is contained anywhere in our list
if (item.toLowerCase().contains(newValue.toLowerCase().trim())) {
return true;
}
// No matches found
return false;
}));
// Finally, let's add the filtered list to our ComboBox
comboBox.setItems(filteredList);
}
}
您將擁有一個簡單的、可編輯的 ComboBox，它可以從列表中過濾掉不匹配的值。
使用這種方法，您不需要監(jiān)聽每個按鍵，但可以在其Predicate自身內(nèi)提供任何過濾指令，如上所示。
結(jié)果：
編輯：
ComboBox但是，可編輯項存在一些問題需要解決，因為從列表中選擇一個項目會引發(fā)IndexOutOfBoundsException.
這可以通過使用單獨TextField的過濾器來緩解，但保持與上述基本相同的代碼。而不是將偵聽器添加到comboBox.getEditor()，只需將其更改為textField。這將毫無問題地過濾列表。
這是使用該方法的完整 MCVE：
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.collections.transformation.FilteredList;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.TextField;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class Main extends Application {
// Create a list of items
private final ObservableList<String> items = FXCollections.observableArrayList();
// Create the search field
TextField textField = new TextField("Filter ...");
// Create the ComboBox
private final ComboBox<String> comboBox = new ComboBox<>();
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage primaryStage) {
// Simple Interface
VBox root = new VBox(10);
root.setAlignment(Pos.CENTER);
root.setPadding(new Insets(10));
// Add sample items to our list
items.addAll("One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten");
createListener();
root.getChildren().addAll(textField, comboBox);
// Show the stage
primaryStage.setScene(new Scene(root));
primaryStage.setTitle("Filtered ComboBox");
primaryStage.show();
}
private void createListener() {
// Create the listener to filter the list as user enters search terms
FilteredList<String> filteredList = new FilteredList<>(items);
// Add listener to our ComboBox textfield to filter the list
textField.textProperty().addListener((observable, oldValue, newValue) ->
filteredList.setPredicate(item -> {
// If the TextField is empty, return all items in the original list
if (newValue == null || newValue.isEmpty()) {
return true;
}
// Check if the search term is contained anywhere in our list
if (item.toLowerCase().contains(newValue.toLowerCase().trim())) {
return true;
}
// No matches found
return false;
}));
// Finally, let's add the filtered list to our ComboBox
comboBox.setItems(filteredList);
// Allow the ComboBox to extend in size
comboBox.setMaxWidth(Double.MAX_VALUE);
}
}
森欄
TA貢獻1810條經(jīng)驗 獲得超5個贊
我發(fā)現(xiàn)的最佳解決方案是稍微修改的版本：JavaFX searchable combobox (like js select2)
我修改的內(nèi)容是使 InputFilter 類通用，并且組合框在關(guān)閉下拉列表后失去焦點。這里的代碼：
import javafx.application.Platform;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.collections.transformation.FilteredList;
import javafx.scene.control.ComboBox;
public class InputFilter<T> implements ChangeListener<String> {
private ComboBox<T> box;
private FilteredList<T> items;
private boolean upperCase;
private int maxLength;
private String restriction;
private int count = 0;
/**
* @param box
* The combo box to whose textProperty this listener is
* added.
* @param items
* The {@link FilteredList} containing the items in the list.
*/
public InputFilter(ComboBox<T> box, FilteredList<T> items, boolean upperCase, int maxLength,
String restriction) {
this.box = box;
this.items = items;
this.upperCase = upperCase;
this.maxLength = maxLength;
this.restriction = restriction;
this.box.setItems(items);
this.box.showingProperty().addListener(new ChangeListener<Boolean>() {
@Override
public void changed(ObservableValue<? extends Boolean> observable, Boolean oldValue, Boolean newValue) {
if (newValue == false) {
items.setPredicate(null);
box.getParent().requestFocus();
}
}
});
}
public InputFilter(ComboBox<T> box, FilteredList<T> items, boolean upperCase, int maxLength) {
this(box, items, upperCase, maxLength, null);
}
public InputFilter(ComboBox<T> box, FilteredList<T> items, boolean upperCase) {
this(box, items, upperCase, -1, null);
}
public InputFilter(ComboBox<T> box, FilteredList<T> items) {
this(box, items, false);
}
@Override
public void changed(ObservableValue<? extends String> observable, String oldValue, String newValue) {
StringProperty value = new SimpleStringProperty(newValue);
this.count++;
System.out.println(this.count);
System.out.println(oldValue);
System.out.println(newValue);
// If any item is selected we save that reference.
T selected = box.getSelectionModel().getSelectedItem() != null
? box.getSelectionModel().getSelectedItem() : null;
String selectedString = null;
// We save the String of the selected item.
if (selected != null) {
selectedString = this.box.getConverter().toString(selected);
}
if (upperCase) {
value.set(value.get().toUpperCase());
}
if (maxLength >= 0 && value.get().length() > maxLength) {
value.set(oldValue);
}
if (restriction != null) {
if (!value.get().matches(restriction + "*")) {
value.set(oldValue);
}
}
// If an item is selected and the value in the editor is the same
// as the selected item we don't filter the list.
if (selected != null && value.get().equals(selectedString)) {
// This will place the caret at the end of the string when
// something is selected.
System.out.println(value.get());
System.out.println(selectedString);
Platform.runLater(() -> box.getEditor().end());
} else {
items.setPredicate(item -> {
System.out.println("setPredicate");
System.out.println(value.get());
T itemString = item;
if (this.box.getConverter().toString(itemString).toUpperCase().contains(value.get().toUpperCase())) {
return true;
} else {
return false;
}
});
}
// If the popup isn't already showing we show it.
if (!box.isShowing()) {
// If the new value is empty we don't want to show the popup,
// since
// this will happen when the combo box gets manually reset.
if (!newValue.isEmpty() && box.isFocused()) {
box.show();
}
}
// If it is showing and there's only one item in the popup, which is
// an
// exact match to the text, we hide the dropdown.
else {
if (items.size() == 1) {
// We need to get the String differently depending on the
// nature
// of the object.
T item = items.get(0);
// To get the value we want to compare with the written
// value, we need to crop the value according to the current
// selectionCrop.
T comparableItem = item;
if (value.get().equals(comparableItem)) {
Platform.runLater(() -> box.hide());
}
}
}
box.getEditor().setText(value.get());
}
}
然后將 InputFilter 添加為 Combobox 的 textField 的更改偵聽器：
comboBox.getEditor().textProperty().addListener(new InputFilter<YourCustomClass>(comboBox, new FilteredList<YourCustomClass>(comboBox.getItems())));
目前Combobox.setEditable(true)必須在外部手動完成，但我計劃將其移入 InputFilter 本身。您還需要為 Combobox 設(shè)置一個字符串轉(zhuǎn)換器。到目前為止，這個解決方案對我來說很糟糕，唯一缺少的是在輸入搜索鍵時支持空格鍵。
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